Carbon quantum dots fluorescence quenching for potassium optode construction.

Photophysical phenomena associated with carbon nanoparticles in combination with biocompatibility and readily functionalizable properties have attracted significant interest for sensing and imaging applications. A potassium ion optode based on the fluorescence quenching of carbon quantum dots (CQDs) was constructed. The CQDs were synthesized using a microwave method, citric acid and 2,2'-(ethylene-dioxy)bis(ethylamine). A quantum yield of 7.1% was calculated for the synthesized CQDs. A linear dynamic range of about one-order of magnitude with a correlation coefficient of 0.99 was obtained. The optode was applied on real samples and a 0.60-1.60% error range was obtained relative to the ion-selective electrode.